538 research outputs found

    Measurements of tidal flow variability in Ramsey Sound, Pembrokeshire

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    The nature of the flow at in-stream tidal energy sites is particularly important for predicting array and device performance, and also for operations and maintenance planning. Previous developers have reported issues such as the choice of vessel, cost of operations, and the limits of operation of deployment vessels. The dynamics of the flow around slack water has been of particular interest at Ramsey Sound in Pembrokeshire (UK) for planning the recovery of an existing turbine, the Tidal Energy Limited ‘Deltastream’. This research presents flow characteristics of Ramsey Sound, based on analysis of Acoustic Doppler Current Profiler (ADCP) measurements and tide gauge data from the nearby Standard Port of Milford Haven. The ADCP was located approximately 300 m across the channel, at the northern end of the channel, where the channel width was 1200 m and the mean depth was approximately 33 m. The flow dynamics were examined specifically to look at times potentially suitable for offshore operations Two weeks of data were used in the analysis, spanning a complete spring-neap cycle. Results demonstrate that flow velocities exhibited clear asymmetry, with stronger flows on the northerly directed flood tide than on the ebb. There was considerable variation in the measured current speed around the time of the maximum, suggesting large scale bed feature generated turbulence. The flood (northerly) current maximum was approximately in phase with high water at Milford Haven. Cross correlation indicated that the flow generally led the elevation by 20 minutes. In contrast to the expected theory, the current strength at mid-depth was stronger than at the surface on the maximum flood tide. The maximum flow speed in the tide was reasonably predictable from the tide range at Milford. A threshold-based analysis of the ADCP measurements allowed the duration of slow-moving water to be identified for operation planning. Operations and planning in light of sound understanding of hydrodynamics at tidal energy sites is critical for future economic success of the tidal energy sector. The results shown here from an ADCP deployment in Ramsey Sound have shown the capability to give useful tools for planning recovery operations

    Discovery of an ultramassive pulsating white dwarf

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    We announce the discovery of the most massive pulsating hydrogen-atmosphere (DA) white dwarf (WD) ever discovered, GD 518. Model atmosphere fits to the optical spectrum of this star show it is a 12,030 +/- 210 K WD with a log(g) = 9.08 +/- 0.06, which corresponds to a mass of 1.20 +/- 0.03 Msun. Stellar evolution models indicate that the progenitor of such a high-mass WD endured a stable carbon-burning phase, producing an oxygen-neon-core WD. The discovery of pulsations in GD 518 thus offers the first opportunity to probe the interior of a WD with a possible oxygen-neon core. Such a massive WD should also be significantly crystallized at this temperature. The star exhibits multi-periodic luminosity variations at timescales ranging from roughly 425-595 s and amplitudes up to 0.7%, consistent in period and amplitude with the observed variability of typical ZZ Ceti stars, which exhibit non-radial g-mode pulsations driven by a hydrogen partial ionization zone. Successfully unraveling both the total mass and core composition of GD 518 provides a unique opportunity to investigate intermediate-mass stellar evolution, and can possibly place an upper limit to the mass of a carbon-oxygen-core WD, which in turn constrains SNe Ia progenitor systems.Comment: 5 pages, 3 figures, Astrophysical Journal Letters, 771, L2 (2013

    The influence of a full-time, immersive simulation-based clinical placement on physiotherapy student confidence during the transition to clinical practice

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    Background: Novice students may have limited learning opportunities during their early exposure to complex clinical environments, due to the priorities of patient care. Immersive, high-fidelity simulation provides an opportunity for physiotherapy students to be exposed to relatively complex scenarios in a safe learning environment before transitioning to the clinical setting. The present study evaluated the influence of immersive simulation on student confidence and competence. Methods: Sixty penultimate year physiotherapy students completed an 18-day full-time immersive simulation placement. The placement involved students spending 6 days working in each of three core practice areas (cardiopulmonary, musculoskeletal, neurological) in which they interacted with simulated patients portrayed by professional role-play actors. The patient scenarios were developed by groups of expert practitioners and incorporated full documentary and imaging information. Students completed a questionnaire to evaluate their confidence in the clinical environment at the start and completion of each 6-day rotation. Their clinical competence was evaluated at the end of each 6-day rotation using the Assessment of Physiotherapy Practice (APP) tool. In a secondary analysis, the clinical competence of this cohort was evaluated in comparison to a matched cohort of students from the same year group that had not completed an immersive simulation placement. Results: Student confidence improved significantly in each 6-day rotation (p < 0.001); however, it reduced again at the commencement of the next rotation, and there was no cumulative improvement in confidence over the 18-day placement (p = 0.22). Students who had completed the immersive simulation placement achieved higher APP (p < 0.001) scores in an evaluation of their competence to practice during their subsequent clinical placement. Conclusion: Immersive simulation provides a beneficial learning environment to enable physiotherapy students to transition from university-based education to working in the clinical environment

    Adherence with urate-lowering therapies for the treatment of gout

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    INTRODUCTION: Adherence to urate-lowering drugs (ULDs) has not been well evaluated among those with gout. Our aim was to assess the level and determinants of non-adherence with ULDs prescribed for gout. METHODS: We identified persons using two integrated delivery systems aged 18 years or older with a diagnosis of gout who initiated use of allopurinol, probenecid or sulfinpyrazone from 1 January 2000 to 30 June 2006. Non-adherence was measured using the medication possession ratio (MPR) over the first year of therapy and defined as an MPR \u3c 0.8. Descriptive statistics were calculated and logistic regression was used to estimate the strength of the association between patient characteristics and non-adherence. RESULTS: A total of 4,166 gout patients initiated ULDs; 97% received allopurinol. Median MPR for any ULD use was 0.68 (interquartile range (IQR) 0.64). Over half of the patients (56%) were non-adherent (MPR \u3c 0.8). In adjusted analyses, predictors of poor adherence included younger age (odds ratio (OR) 2.43, 95% confidence interval (CI) 1.86 to 3.18 for ages \u3c45 and OR 1.44, 95% CI 1.08 to 1.93 for ages 45 to 49), fewer comorbid conditions (OR 1.46, 95% CI 1.20 to 1.77), no provider visits for gout prior to urate-lowering drug initiation (OR 1.28, 95% CI 1.05 to 1.55), and use of non-steroidal anti-inflammatory drugs in the year prior to urate-lowering drug initiation (OR 1.15, 95% CI 1.00 to 1.31). CONCLUSIONS: Non-adherence amongst gout patients initiating ULDs is exceedingly common, particularly in younger patients with less comorbidity and no provider visits for gout prior to ULD initiation. Providers should be aware of the magnitude of non-adherence with ULDs

    Clomifene citrate or unstimulated intrauterine insemination compared with expectant management for unexplained infertility: pragmatic randomised controlled trial

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    Objective To compare the effectiveness of clomifene citrate and unstimulated intrauterine insemination with expectant management for the treatment of unexplained infertility

    Long-term low dose nitisinone therapy in adults with alkaptonuria shows no cognitive decline or increased severity of depression.

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    Little is documented on whether nitisinone-induced hypertyrosinaemia alters cognitive functioning or leads to worsening depression in alkaptonuria (AKU). Wechsler Adult Intelligence Scale-IV (WAIS-IV) and Beck Depression Inventory-II (BDI-II) assessments were performed before and annually following treatment with nitisinone 2 mg daily to assess the impact on cognitive functioning and severity of depression. Serum tyrosine concentrations were also measured annually. WAIS-IV: 63 patients (27 females/36 males: mean age[years] [±standard deviation, range] 55.7[13.7, 26-79]; 60.3[9.6, 19-75]) were included at baseline for assessment of: verbal comprehension (VC), perceptual reasoning (PR), working memory (WM), and processing speed (PS) using separate indices. Over the 6-year period studied 43, 39, 36, 29, 26 and 15 patients had annual assessments. Using a longitudinal model (age and sex adjusted) no significant differences were observed in any of the indices over this period, apart from VC which showed a significant increase after adjustment for sex (p BDI-II: 74 patients (32 females/42 males: mean age[years] [±standard deviation, range] 56.1[13.2, 26-79]; 42 males, 51.5[16.3, 19-70]) were included at baseline. Over the 7-year period studied 48, 47, 38, 34, 32, 24 and 12 patients had annual assessments. No significant differences in BDI-II scores were observed when compared to baseline. Hypertyrosinaemia was observed in all patients following treatment with nitisinone (p < 0.001, at all annual visits). Serum tyrosine was not correlated with WAIS-IV sub-test indices or BDI-II scores pre- or post-nitisinone therapy. These findings suggest that treatment with nitisinone does not affect cognitive functioning and or lead to increased severity of depression

    A Mixed-Methods Study To Characterize Pharmaceutical Marketing in the Nursing Home Setting: Off-Label Use of Atypical Antipsychotics

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    Background: Despite FDA warnings that atypical antipsychotic medications are associated with an increased risk of death when used to treat behavioral disorders in older adults with dementia, they are prescribed to nearly one-third of older U.S. nursing home (NH) residents. Reasons for their high use in NHs are poorly understood, but may include pharmaceutical marketing efforts in the NH setting. Methods: This study is nested within an ongoing cluster randomized trial to improve the use of atypical antipsychotics in NHs. We analyzed semistructured interviews (n = 36) and surveys (n = 139) of administrators, directors of nursing and medical directors from 62 NHs in Connecticut. Using prescription drug claims from a national long-term care pharmacy, we arrayed study NHs into lowest to highest tertile of atypical antipsychotic use. We tested for differences in the receipt of information or clinical tools from pharmaceutical company representatives (PCRs) to manage dementia-related behaviors by medication use tertiles, adjusting for NH profit status, size, quality (overall, health inspections, staffing) and staffing measures (daily nurse hours per resident). Results: Average baseline use of atypical antipsychotics ranged from 6.6 to 44.3 percent of all residents in the facility. Approximately one-quarter of NH leaders presently receive information on dementia-related behavioral management strategies from PCRs through detailing, in-service training, written or Web-based material or sponsorship as speakers. However, we did not detect statistically significant differences in the receipt of information by level of atypical antipsychotic use, NH characteristics, quality and staffing measures. Conclusions: This first attempt to characterize pharmaceutical marketing within the NH setting did not find differences among reports of marketing efforts with respect to medication use and facility-level characteristics. However, studies across a wider geographic area should continue investigating the possible role of marketing efforts on overall use and choice of atypical antipsychotics in the NH setting

    Patterns of analgesic use, pain and self-efficacy: a cross-sectional study of patients attending a hospital rheumatology clinic

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    Background: Many people attending rheumatology clinics use analgesics and non-steroidal anti-inflammatories for persistent musculoskeletal pain. Guidelines for pain management recommend regular and pre-emptive use of analgesics to reduce the impact of pain. Clinical experience indicates that analgesics are often not used in this way. Studies exploring use of analgesics in arthritis have historically measured adherence to such medication. Here we examine patterns of analgesic use and their relationships to pain, self-efficacy and demographic factors. Methods: Consecutive patients were approached in a hospital rheumatology out-patient clinic. Pattern of analgesic use was assessed by response to statements such as 'I always take my tablets every day.' Pain and self-efficacy (SE) were measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Arthritis Self-Efficacy Scale (ASES). Influence of factors on pain level and regularity of analgesic use were investigated using linear regression. Differences in pain between those agreeing and disagreeing with statements regarding analgesic use were assessed using t-tests. Results: 218 patients (85% of attendees) completed the study. Six (2.8%) patients reported no current pain, 26 (12.3%) slight, 100 (47.4%) moderate, 62 (29.4%) severe and 17 (8.1%) extreme pain. In multiple linear regression self efficacy and regularity of analgesic use were significant (p < 0.01) with lower self efficacy and more regular use of analgesics associated with more pain. Low SE was associated with greater pain: 40 (41.7%) people with low SE reported severe pain versus 22 (18.3%) people with high SE, p < 0.001. Patients in greater pain were significantly more likely to take analgesics regularly; 13 (77%) of those in extreme pain reported always taking their analgesics every day, versus 9 (35%) in slight pain. Many patients, including 46% of those in severe pain, adjusted analgesic use to current pain level. In simple linear regression, pain was the only variable significantly associated with regularity of analgesic use: higher levels of pain corresponded to more regular analgesic use (p = 0.003). Conclusion: Our study confirms that there is a strong inverse relationship between self-efficacy and pain severity. Analgesics are often used irregularly by people with arthritis, including some reporting severe pain
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